Gear unit

ABSTRACT

A gear unit in which a cable, band or similar device is fitted between the drive and the output in order to transform a fast rotational movement at the drive end, which is limited in both directions, into a slow rotational movement at the output end. The cable is fastened at both ends to an oscillating intermediary single-piece divided into two segments, and rests against the outer walls of the intermediary piece and is wound around the shaft of the drive so as to transfer a driving torque. A position sensor is assigned to the inner segment of the intermediary piece, and/or a torque sensor is mounted between both segments of the intermediary piece. A fast rotational movement of the drive is transformed into a slow rotational movement without play, and provides a good synchronization characteristic.

The present application is a CIP of copending parent application Ser.No. 09/424,957, filed as PCT/EP98/033731 on Jun. 5, 1998, and publishedin a language other than English, and with the English text having beenfiled in the parent application upon entry into the U.S. National Stageon Dec. 6, 1999.

FIELD OF THE INVENTION

The present invention relates to a gear unit for converting a fast,drive-side rotational movement that is limited in both directions into aslow rotational movement on the output side.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 5,105,672 discloses a unit of this general type, in whicha force-transmitting element in the form of at least one cable isprovided between the drive and the output.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a gear unit that operateswithout play, and has a good synchronization characteristic, with anoutput that only fluctuates slightly when the input rpm remainsunchanged, and with which positions can be determined and/or torques orforces can be detected.

In accordance with the invention, this object is accomplished by a gearunit for converting a fast, drive side rotational movement that islimited in both directions into a slow rotational movement on the outputside, the unit being characterized in that the force-transmittingelement acts on a one-piece, pivotably-seated intermediate part that isdivided into two segments, with a position sensor being associated withan inside segment of the intermediate part, or a torque sensor beingprovided between the two segments of the intermediate part.

Thus, the gear unit of the invention, a force-transmitting element actson a one-piece intermediate part that is divided into two segments andseated to pivot. A position sensor is allocated to an inside segment ofthe intermediate part, and/or a torque sensor is disposed between thetwo segments of the intermediate part.

In accordance with a preferred modification of the invention, theintermediate part comprises the inside segment and an approximatelyU-shaped outside segment that partially surrounds the inside segment. Aslot that extends in an approximate U-shape is provided between the twosegments. Furthermore, the two legs of the U-shaped outside segment arethinner than a center part that connects these two legs to one another.

In accordance with a preferred embodiment of the gear unit of theinvention, a cable, band or the like is provided as a force-transmittingelement between the drive and the output; and the two ends of theelement are secured to the pivotably-seated intermediate part. The cableextends against the outer sides of the intermediate part, and is woundonce or multiple times around the shaft of the drive, preferably in theform of an electric motor, for transmitting a drive moment.

In accordance with a further preferred embodiment of the invention, theforce-transmitting element is a frictional wheel that is provided at thedrive shaft and rests, in a frictional lockup, against the outer surfaceof the outside segment of the intermediate part, the surface beingprovided as a frictional surface. In a further preferred embodiment ofthe gear unit of the invention, the force-transmitting element is atoothed wheel that is secured to the drive shaft and is in anon-positive engagement with a toothing that is embodied on the outersegment and corresponds to a toothed rack.

According to the invention, on one side of the inside segment, anopto-electronic, position-sensitive detector is associated with theposition sensor that is associated with the inside segment of theintermediate part, and a light source is provided on the other side.Between these, a slot that extends with a radially changing (e.g.,spiral-shaped) course is provided in the inside segment. The shape—forexample, a spiral—of the slot is selected such that a linear connectionis formed between an angular change in the intermediate part and thedisplacement of the light beam on the detector.

Also in accordance with the invention, a torque sensor is or can beprovided at the two segments of the intermediate part. Anopto-electronic, position-sensitive detector that serves as a torquesensor is mounted in the center of a center part of the outside segment.On the other side of a slot embodied between the inside and outsidesegments, a slotted screen is mounted to the inside segment directlyopposite the detector; a light source is disposed behind this screen.

According to the invention, therefore, a mechanical gear is produced,which converts a fast rotational movement of the drive that is limitedin both directions into a slow rotational movement of the output, thetransmission being effected without play and with a good synchronizationcharacteristic. According to the invention, a sensor mechanism in theform of the position sensor and/or the torque sensor is integrated intothe gear unit, the former generally determining the position and/or thelatter measuring the torque of the drive or output. In the presentinvention, one or both of the two optical sensors is or are directlyintegrated into the gear unit in an especially compact manner.

Because of the special design of the U-shaped outside segment, theelectro-optical, position-sensitive detector which operates as a torquesensor and is mounted in the center of the outside segment can detect abending in the two legs of the U-shaped outside segment, which act likebending girders that are clamped on one side; this bending correspondsto the torque that is applied in the drive or output direction,respectively, and from which a corresponding force can be calculated ina known manner. Thus, a force-reflecting sensor mechanism is created,with which the force that is decisive in any type of tactile processescan ultimately be detected.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described in detail below,with reference to the attached drawings, wherein:

FIG. 1 is a front view, in perspective, of essentially an intermediatepart of a gear unit according to the invention;

FIGS. 2a and 2 b are front view and a plan view, respectively, also inperspective, of the intermediate part of the gear unit of the invention,with an installed position sensor;

FIG. 3 is a front, perspective view, which corresponds to that of FIG.1, of the intermediate part of the gear unit according to the invention,with installed position sensor and torque sensor, it being understoodthat the present invention includes the presence of either said sensorwithout the presence of the other said senor;

FIG. 4 is a plan view, in perspective, of a part of the intermediatepart, with an installed torque sensor;

FIG. 5 is a front, perspective view, which corresponds to the rightportion of FIG. 3, of the intermediate part of the gear unit accordingto a second preferred embodiment of the invention, with an installedposition sensor and torque sensor, it again being understood that eitherof these sensors may be used in the absence of the other; and

FIG. 6 is a front, perspective view, which corresponds to the rightportion of FIG. 3, of the intermediate part of the gear unit accordingto a third preferred embodiment of the invention, with an installedposition detector and torque sensor, either or both of which may bepresent.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a plan view, in perspective, of an intermediate part 3 of agear unit 1. The intermediate part 3 is pivotably-seated in the wall ofa housing, not shown in detail, by way of a pivoting pin 36.

The one-piece intermediate part 3 is divided by a slot 34 into an insidesegment 31 and an outside segment 32, which partially surrounds thesegment 31 and is approximately U-shaped in the plan view. A center part323 of the outside segment 32 makes a transition into two legs 321 and322, which, in the plan view, are considerably narrower, i.e.considerably thinner in cross section, than the center part 323connecting them.

FIG. 1 indicates a cable 2, which is secured by one end 21 in anadjustable clamping device 23, while the other cable end 22 is held in arecess 37 indicated in the upper region of the intermediate part 3.

In FIG. 1, the cable extends, from the clamping device 23, against thelower outer surface of the intermediate part 3, is wrapped with one orpreferably several windings 20 (FIGS. 2a and 3) around a shaft 41 of adrive 4, preferably in the form of an electric motor, then lies againagainst the upper outer surface of the intermediate part 3. The numberof windings 20, for example three in FIGS. 2b and 3, depends on thedriving torque to be transmitted, which acts through a frictional ornon-positive lockup on the cable 2.

Moreover, the magnitude of a torque conversion depends on the ratios ofthe radii, namely the radius of the intermediate part 3 from the centerof the pivoting pin 36 to the outside edge of the center part 323 of theoutside segment 32 in relation to the radius of the drive shaft 41.Thus, the ratios of the radii of the drive and intermediate-partsurfaces rolling onto one another determine the magnitude of the torqueconversion. If, in a preferred embodiment of the gear unit of theinvention, the cable that is clamped on both sides is used to couple thedrive shaft 41 and the intermediate part comprising two segments, aplay-free gear having a high efficiency and very good synchronizationcharacteristics is created.

FIGS. 2a and 2 b show a front view and a plan view, respectively, of theright portion (in FIG. 1) of the intermediate part 3, and the drivemotor 4 with its drive shaft 41. FIGS. 2a and 2 b further show aposition sensor, which is indicated in its entirety by 5, and is formedfrom an opto-electronic, position-sensitive detector 51, which isdisposed on the one side, in FIG. 2a the front side, of the intermediatepart 3, and a light source 53 that is disposed on the other side, inFIG. 2b the rear side, of the intermediate part 3.

A spiral-shaped slot 52 is provided between the opto-electronic,position-sensitive detector 51 serving as a position sensor 5 and thelight source 53 such that the part of the spiral slot that enters theregion of the position sensor extends approximately in a straight line,although it is shifted radially during the pivoting movement.

Because of its special design, the slot 52 moves back and forth in astraight line in front of the opto-electronic, position-sensitivedetector 51 serving as a position sensor 5, specifically perpendicularto the longitudinal axis of the detector, during a pivoting movement ofthe intermediate part 3 about the pivoting pin 36.

Furthermore, both FIGS. 1 and 2a show recesses 35 in the intermediatepart 3, in which the torque sensor 6 is optionally accommodated, as willbe described in detail below in connection with FIGS. 3 and 4.

The perspective illustration of FIG. 3 essentially corresponds to thatof FIG. 1, with the difference that in FIG. 3, the torque sensor 6 isschematically represented in perspective in addition to theopto-electronic position-sensitive detector 51 of the position sensor 5.

Here, the torque sensor 6 includes a light source 63 and anopto-electronic, position-sensitive detector 61, which is mounted in thecenter of the center part 323 of the outside segment 32. A slottedscreen 62 is mounted to the inside segment 32, between the two elements61 and 63. Also, FIG. 2a schematically indicates the windings 20—forexample, three—of the cable 2 as being wound around the motor shaft 41.

FIG. 4 is merely an enlarged view of the right part—in FIG. 3—of thesegments 31 and 32 of the intermediate part 3, the drive 4 and inparticular the torque sensor 6.

FIG. 5 is a front, perspective view, which corresponds to the rightportion of FIG. 3, of the intermediate part 3′ of a second preferredembodiment of the gear unit according to the invention, with aninstalled position sensor 5 and torque sensor 6, either o which may beomitted. In FIG. 5, all of the parts that have already been described inconjunction with FIGS. 1 through 4 are provided with the same referencecharacters, and therefore are not explained again.

The second embodiment in FIG. 5 differs from the embodiment shown inFIGS. 1 through 4 in that a frictional wheel 42 provided at the driveshaft 41′ is used as the force-transmitting element, instead of thecable 2; this wheel rests, in a frictional lockup, against the outersurface 324 of the center part 323′ of the outside segment 32′ of theintermediate part 3′, the outer surface being embodied as a frictionalsurface.

Unlike FIG. 5, the third preferred embodiment of the invention, which isshown in FIG. 6, has a toothed wheel 43 as a force transmitting element,which is secured to the drive shaft 41 and meshes in a non-positivelockup with a toothing 325 provided on the center part 323″ of theoutside segment 32″ and corresponds to a toothed rack.

In the second and third embodiments of the gear unit according to theinvention, as shown in FIGS. 5 and 6, the magnitude of a torqueconversion again depends on the ratio of the radii, namely the radius ofthe intermediate part 3, which extends from the center of the pivotingpin, not shown in FIGS. 5 and 6, to the outside edge of the center part323′, 323″ of the outside segment 32′, 32″, respectively, in relation tothe radius of the frictional wheel 42, or the diameter of the pitchcircle of the toothed wheel 43 secured to the drive shaft 41. Thus, inthese embodiments the ratios of the radii of the surfaces rolling ontoone another, or the engaged toothings of the drive 4 and theintermediate part 3′, 3″, determine the magnitude of the torqueconversion.

If the intermediate part 3 is pivoted counterclockwise, the two legs 321and 322 of the outside segment 3, which can be viewed as bending girdersthat are held or clamped on one side, i.e., on the inside segment 31, Sare “bent” downward in FIGS. 3, 5 or 6, or “bent” upward during aclockwise pivoting movement.

During a bending process of this nature, the light. beam passing throughthe slotted screen 62 of the torque sensor 6 travels upward during acounterclockwise pivoting movement in FIG. 3, or downward during aclockwise pivoting movement in FIGS. 3, 5 or 6. This movement of thelight beam due to the relative movement between the slotted screen 62and the opto-electronic, position-sensitive detector 61 of the torquesensor 6 is detected by the torque sensor; the position of the incidentlight beam is consequently measured.

The torque of the drive and output can be derived from the change in theposition of the light beam on the detector 61 and the geometry of thetwo legs 321 and 322 acting as bending girders.

In accordance with the present invention, therefore, both a positionsensor and a torque sensor, when both are present, are integrated in acompact manner into the mechanics of a play-free gear having a very goodsynchronization characteristic; when only one sensor is present, it issimilarly integrated. Therefore, with the present invention, anextremely economical and precise, analog, optical measuring system iscreated, which is integrated in a compact manner into the gear unit, andwith which either or both the position and torque can be measured.

According to the invention, the gear unit 1 with the integrated sensormechanism in the form of the position sensor 5 and the torque sensor 6can generally be used to detect tactile processes.

Two gear units 1 having an integrated sensor mechanism (5, 6) can beconnected to an input device that detects the respective pivotingposition and transmits the force.

Also according to the invention, a gear unit 1 can be used to act upon agas pedal with a force, in which case the vehicle driver is provided ina tactile manner with a force that counteracts his force on the gaspedal when, for example, the vehicle passes a road sign whose positionis detected in a vehicle-navigation system. Through this tactileprocess, the vehicle link receives a distinct indication to reduce speedwhen passing the road sign. Furthermore, in accordance with theinvention, a gear unit 1 can be used to act upon a brake pedal thattransmits a force. A gear unit 1 can also be used to act upon a steeringwheel that transmits a force.

According to the invention, one or more gear units can be used to setthe headlights of a motor vehicle. Moreover, in accordance with theinvention, at least one gear unit having an integrated sensor mechanismcan be used as a robotic link.

Also in accordance with the invention, two gear units can be connectedand switched so as to create a stick in an aircraft that transmitsforces.

Through the use of at least one gear unit, an input and control devicethat transmits forces can be created, with which assembly procedures,such as joining processes, can be performed.

At least one gear unit according to the invention can also be used as aforce-transmitting input and control device, with which, for example,wheelchairs of disabled individuals can be rendered controllable.

The foregoing description of the specific embodiments will so fullyreveal the general nature of the invention that others can, by applyingcurrent knowledge, readily modify and/or adapt for various applicationssuch specific embodiments without undue experimentation and withoutdeparting from the generic concept, and, therefore, such adaptations andmodifications should and are intended to be comprehended within themeaning and range of equivalents of the disclosed embodiments. It is tobe understood that the phraseology or terminology employed herein is forthe purpose of description and not of limitation. The means, materials,and steps for carrying out various disclosed functions may take avariety of alternative forms without departing from the invention.

Thus the expressions “means to . . . ” and “means for . . . ”, or anymethod step language, as may be found in the specification above and/orin the claims below, followed by a functional statement, are intended todefine and cover whatever structural, physical, chemical or electricalelement or structure, or whatever method step, which may now or in thefuture exist which carries out the recited function, whether or notprecisely equivalent to the embodiment or embodiments disclosed in thespecification above, i.e., other means or steps for carrying out thesame functions can be used; and it is intended that such expressions begiven their broadest interpretation.

What is claimed is:
 1. A gear unit for converting a fast, drive-siderotational movement that is limited in both directions into a slowoutput movement by a force-transmitting element, which is providedbetween a drive and an output, characterized in that theforce-transmitting element (2; 42, 324; 43, 325) acts on a one-piece,pivotably-seated intermediate part (3; 3′, 3″) that is divided into twosegments (31; 32, 32′, 32″), with a position sensor (5) being associatedwith an inside segment (31) of the intermediate part, or a torque sensor(6) being provided between the two segments of the intermediate part. 2.The gear unit according to claim 1, characterized in that theintermediate part (3, 3′, 3″) comprises the inside segment (31) and anapproximately U-shaped outside segment (32, 32′, 32″) that partiallysurrounds the inside segment (31), with a slot (34) that extends in anapproximate U shape being embodied between the two segments.
 3. The gearunit according to claim 2, characterized in that two legs (321, 322) ofthe approximately U-shaped outside segment (32, 32′, 32″) are thinnerthan a center part (323, 323′, 323″) that connects the legs to oneanother.
 4. The gear unit according to claim 1, characterized in thatthe force-transmitting element is a cable or a band (2) that is securedby both ends (21, 22) to the pivotably-seated intermediate part (3),extends along and against outer sides of the intermediate part and iswound around a shaft (41) of the drive (4) for a non-positive-lockuptransmission of a driving torque.
 5. The gear unit according to claim 1,characterized in that the force-transmitting element is a frictionalwheel (42) that is provided at the drive shaft (41′) and rests, in africtional lockup, against the outer surface (324) of an outside segment(32′) of the intermediate part (3′), the outer surface being embodied asa frictional surface.
 6. The gear unit according to claim 1,characterized in that the force-transmitting element is a toothed wheel(43) that is secured to a drive shaft (41) and is in a non-positiveengagement with a toothing (325) that is embodied on an outside segment(324) and corresponds to a toothed rack.
 7. The gear unit according toclaim 1, characterized in that an opto-electronic, position-sensitivedetector (61) serving as a torque sensor (6) is mounted in the center ofa center part (32, 323′, 323″) of an outside segment (32, 32′, 32″),and, on the other side of a slot (34) embodied between the inside andoutside segments, a slotted screen (62) is mounted to the inside segment(31) directly opposite the detector, with a light source (63) beingdisposed behind this screen.
 8. The gear unit according to claim 1,characterized in that a slot (52) having a radially-variable course isembodied in the region of the inside segment (31), with which theposition sensor (5) is associated, with an opto-electronic,position-sensitive detector (51) that serves as a position detector (5)being associated with the sensor on one side of the inside segment (31),and a light source (53) being associated with the sensor on the otherside of the inside segment (31).
 9. The gear unit according to claim 4,characterized in that an adjustable cable-tension device (23) isaccommodated at one end (21) of the cable (2), on the side of theintermediate pare (3) opposite the torque sensor (6).
 10. A methodcomprising using at least two gear units according to any one of claims1 through 9, which are connected to an input device that transmits aforce.